Optimizing MPI Programs through Compiled Communication

消息传递接口(MPI)的标准化导致了使用MPI开发的大量应用程序。当前的MPI标准隐藏了网络细节，并为通信提供了简单的接口。虽然这些功能简化了并行编程的任务，但它们限制了通信优化的机会。具体地说，使用当前的MPI，通信优化既可以由编译器执行，也可以在库实现中执行。在这两种情况下，优化都是有限的。编译器执行的优化必须与体系结构无关，因为库对编译器隐藏了体系结构细节。库实现中的优化通常依赖于体系结构。然而，这种优化只能应用于每个单独的例程。在本研究中，我们提出通过编译通信来优化MPI程序。编译后的通信同时利用应用通信信息和系统架构信息进行通信优化，克服了传统通信系统的局限性。我们将通过开发系统来完成拟议的工作，这些系统允许程序员编写常规的可移植MPI程序，并享受通过编译通信实现的高通信性能。该系统还可用于优化现有的MPI程序。我们将集中在这项研究的两个相关部分：通过添加新的例程来扩展MPI标准以支持编译的通信，以及开发一个重构编译器来分析MPI程序并将程序转换为使用编译的通信技术的程序。我们还将开发将编译后的通信应用于不规则问题的技术，并研究库和编译器对编译后通信的支持之间的交互。

The standardization of Message Passing Interface (MPI) has resulted in a large number of applications being developed using MPI. The current MPI standard hides network details and provides a simple interface for communication. While these features ease the task of parallel programming, they limit communication optimization opportunities. Specifically,with the current MPI, communication optimizations can be performed either by the compiler or in the library implementation. In both cases,optimizations are limited. Optimizations performed by the compiler must be architecture independent since the library hides architectural details from the compiler. Optimizations in the library implementation are usually architecture dependent. However, such optimizations can only be applied to each individual routine.In this research, we propose to optimize MPI programs through compiled communication. By simultaneously using the application communication information and the system architecture information to perform communication optimizations, compiled communication overcomes thelimitations in the traditional communication system. We will accomplish the proposed work by developing systems that allow programmers to write regular portable MPI programs and enjoy the high communication performance achieved through compiled communication. The systems can also be used to optimize existing MPI programs. We will concentrate on two related parts of this research: extending the MPI standard by adding new routines to support compiled communication, and developing a restructuring compiler that analyzes an MPI program and transforms the program into one that employs the compiled communication technique. We will also develop techniques for applying compiled communication to irregular problems and investigate the interaction between the library and the compiler support for compiled communication.